The present invention relates to an internal combustion engine with reduced fuel consumption and increased power and efficiency.
Experience has shown that varying the piston displacement in an internal combustion engine to match load requirements can result in substantial fuel savings. Additionally, adjusting the displacement ratio as the load changes can result in further advantages.
The conventional reciprocating combustion engine uses a piston to compress a working fluid in a cylinder chamber. The fluid is then ignited by a spark and the resultant explosion drives the piston a fixed distance along the length of the cylinder. The energy generated by the ignition, and the subsequent linear movement of the piston, is transmitted through a piston rod which is connected to a rotating crank shaft, by way of bearings or other connection means which allow a pivotal connection to the piston on one end and the crank shaft on the other.
The conventional internal combustion engine is designed so that peak power and peak efficiency are available when the engine operates at full load. As a result, operation of the engine at partial load results in a reduced efficiency. When a conventional engine is operated at less than full load, less power is needed, and the power output is therefore reduced by throttling back the air-fuel mixture. This reduces pressure in the cylinder and increases the residual gas content following combustion, thus resulting in decreased operating efficiency.
The preferred approach to increase efficiency is to adjust the piston displacement or stroke length to obtain the maximum power requirement for each operating regime while maintaining the engine at full throttle. This may be done while either maintaining a fixed compression ratio, or adjusting the compression ratio. Reducing the length of the piston stroke will also reduce friction, thus additionally improving efficiency.
The prior art shows various mechanisms and linkage arrangements for varying the stroke length and compression ratio. However, these designs have now been successfully commercialized, most likely because they were complicated, unreliable or mechanically inoperable. One improved mechanism for varying stroke length and compression ratio is disclosed in my copending application Ser. No. 08/061,013 filed May 14, 1993.
Thus, there is a need for a simple mechanical arrangement which will allow for readily adjustable controlled variation of piston displacement and, if desired, adjustment of compression ratio as the power demand of an engine changes.